Stamps, along with signatures, can be considered as the most widely used extrinsic security feature in paper documents. In contrast to signatures, however, for stamps little work has been done to automatically verify their authenticity. In this paper, an approach for verification of color stamps is presented. We focus on photocopied stamps as nongenuine stamps. Our previously presented stamp de...

Subtle variations in ink color and paper of postage stamps can affect their value and desirability to collectors and investors. Protoninduced Xray emission spectrometry (PIXE) is a generally nondestructive forensic analysis tool that reveals the concentrations of chemical elements in a sample. PIXE has been used for more than 30 years, sometimes in conjunction with other analytical methods, to ...

Increasing the per-unit cost of tobacco products is one of the strongest interventions for tobacco control. In jurisdictions with higher taxes in the U.S., however, cigarette pack litter studies show a substantial proportion of littered packs lack the appropriate tax stamp. More limited but still present counterfeiting also exists. We sought to examine the role of tobacco retailers as a source ...